Conversion element, optoelectronic component and method for producing a conversion element

ABSTRACT

A conversion element, an optoelectronic component, an arrangement and a method for producing a conversion element are disclosed. In an embodiment an arrangement includes a conversion element having a wavelength converting conversion material, a matrix material in which the conversion material is embedded and a substrate on which the matrix material with the embedded conversion material is directly arranged, wherein at least one condensed sol-gel material, and a laser source configured to emit primary radiation during operation, wherein the conversion element is arranged in a beam path of the laser source, wherein the conversion element is mechanically immovably mounted with respect to the laser source, and wherein the primary radiation of the laser source is dynamically arranged to the conversion element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No.16/488,216, entitled “Conversion Element, Optoelectronic Component andMethod for Producing a Conversion Element,” which was filed on Aug. 22,2019, which is a national phase filing under section 371 ofPCT/EP2018/053911, filed Feb. 16, 2018, which claims the priority ofGerman patent application 102017104128.1, filed Feb. 28, 2017, all ofwhich is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The invention relates to a conversion element. The invention furtherrelates to an optoelectronic component. The invention further relates toa method for producing a conversion element.

BACKGROUND

In so-called LARP applications (Laser Activated Remote Phosphor), it isnecessary to generate a high luminance. In addition, a small spotwidening is important, i.e., to what extent the illuminated area (forexample, related to 1/e² value of the maximum) of the convertedradiation increases compared to the illuminated area (=excitation area)of the exciting laser beam, the contrast between areas that are to beilluminated and areas that are not to be illuminated (for example, foradaptive spotlights), the color homogeneity over the converter surfaceand over the beam angle, the efficiency and/or the stability (forexample, against humidity, radiation, temperature, chemical influencesetc. in order to guarantee a long life time of the component).

The term LARP applications are used here and in the following to referto applications that use a laser source comprising at least one laserbeam to make a conversion element usable as a light source. This doesnot exclude that part of the laser light is still present and can thuscontribute to the total emission.

SUMMARY OF THE INVENTION

Embodiments provide a conversion element that is suitable for LARPapplications, in particular stable for LARP applications or has a highluminance. Further embodiments provide an optoelectronic componentsuitable for LARP applications. Yet other embodiments provide a methodfor producing a conversion element which produces a stable conversionelement.

In at least one embodiment, the conversion element comprises at leastone or exactly one wavelength converting conversion material. Theconversion element comprises at least one matrix material. The at leastone conversion material is introduced or embedded in the matrixmaterial. The conversion element comprises a substrate. The at least onematrix material and the at least one conversion material are arranged,in particular directly, onto or on the substrate.

Here, direct means that no further layers or elements are arrangedbetween the matrix material and/or conversion material and thesubstrate. In other words, the conversion element can be attached to thesubstrate adhesive-free. The conversion element is therefore notattached to the substrate with another adhesive material. The substratemay have other layers, which, for example, form the coating of thesubstrate. The coating can be formed dichroically. Additionally oralternatively, the substrate can have an anti-reflection coating.

The matrix material comprises or consists of at least one condensedsol-gel material selected from the following group: water glass, metalphosphate, aluminum phosphate, monoaluminum phosphate, modified aluminumphosphate, alkoxytetramethoxysilane, tetraethylorthosilicate,methyltrimethoxysilane, methyltriethoxysilane, titanium alkoxide, silicasol, metal alkoxide, metalloxane, metalalkoxane. The conversion elementis arranged in the beam path of a laser or light source.

The conversion element is optionally mounted mechanically immovable withrespect to the laser source or light source. Here, mechanicallyimmovable means in particular that the relative spatial position of theconversion element and the laser source does not change. The lasersource can comprise at least one laser beam whose beam direction doesnot change spatially relative to the conversion element. Alternatively,the laser source, preferably including primary beam-guiding optics, canhave at least one laser beam that can vary its beam direction. Thevariation of the beam direction can be realized by differenttechnologies. This includes, for example, MEMS (micro-electro-mechanicalsystem) elements or piezo drives, but also polygon mirrors/rotatingrollers, but also typical technologies used in CD and blue ray playerssuch as “Voice Coil Actuators” can be used here. In general, alltechnologies can be used that allow a laser beam to be scanned over theconverter together with primary optical elements. The converter can beused in transmittive or reflective configuration. The describedconverter element can be used particularly advantageously in combinationwith such technologies in a system in scanning LARP systems, especiallyin the AM field (AM=automotive). A detailed description of these systemsis presented below.

The deflection occurs preferably or exclusively via the movement ofeither one or more optical elements such as mirrors and/or lenses.

In particular, the radiation of the laser source is dynamically arrangedto the conversion element.

The inventors have recognized that the use of the conversion elementdescribed here in a LARP assembly has improved heat dissipation,radiation and temperature stability compared to a conventionalconversion element comprising organic matrix materials such as siliconesor epoxides.

Very thin layers comprising a high proportion of conversion material inthe matrix material can be produced. The conversion element can exhibithigh light scattering and is preferably formed exclusively frominorganic materials. Preferably, the conversion material and the matrixmaterial are arranged on a transmissive substrate. In other words, thematrix material can be highly filled with the conversion material andthus very thinly shaped as a layer. In addition, the conversion elementmay have a scattering over pores in the layer and over refractive indexdifferences of the materials. The matrix material with the conversionmaterial is formed in particular as a layer and can be applied directlyto the substrate, i.e., without an additional organic or inorganicadhesive layer.

Previously known conversion elements for LARP applications show thedisadvantage of spot widening and/or poor contrast. However, theseparameters are very important, for example, for automotive applications,such as the use of conversion elements in a headlight, especially forapplications targeting an ADB (Advanced Driving Beam) system, also knownas “Glare-Free HB”. These systems can be realized with one of the abovementioned beam direction deflection technologies. Here, one or morelaser beams are scanned over a conversion element. This can be realizedin one or two dimensions. The resulting local converted lightdistribution is imaged into the far field by secondary optics. Bysynchronizing the laser driver and beam deflection elements, a targetedcontrol of the light distribution can be achieved, including switchingoff and/or dimming the laser and thus also the resulting lightdistribution in certain areas. This can be used to fade out other roadusers (oncoming and preceding vehicles, etc.). As soon as these havedisappeared from the field of vision of the headlights, the de-glaringzone can be fully illuminated again. In order to achieve goodperformance especially in vertical and horizontal de-glaring zones, itis essential to optimize the topics of spotlight widening and contrast.Examples and measurement data for the advantages to be achieved here canbe found in the corresponding figures. Legal regulations can be found inthe well-known ECE-R 123 standard, for example, the use of conversionelements in a headlight.

But also other light distributions such as dimmed headlights or foglights require sufficient sharpness and contrast in the verticaldirection to meet the legal requirements of ECE-R 19 and ECE-R 112.

According to at least one embodiment, the conversion element comprisesat least one wavelength converting conversion material. The conversionmaterial absorbs radiation with a first dominant wavelength (and asurrounding spectral range, if applicable) and converts radiation with asecond dominant wavelength (and a surrounding spectral range, ifapplicable) that is preferably greater than the first dominantwavelength. The dominant wavelength is known to a person skilled in theart and is therefore not explained in detail at this point. Inorganicmaterials with wavelength-converting properties can preferably be usedas conversion materials. For example, a well-known phosphor such asgarnet, orthosilicate and/or nitridosilicate is suited as conversionmaterial. Materials for the conversion material are, for example:

(Y,Gd,Tb,Lu)₃(Al,Ga)₅O₁₂:Ce³⁺;

(Sr,Ba,Ca,Mg)₂Si₅N₈:Eu₂ ⁺;

(Ca,Sr)₈Mg(SiO₄)₄Cl₂:Eu²⁺;

(Sr,Ba,Ln)₂Si(O,N)₄:Eu²⁺ with Ln: at least one element of thelanthanides;

(Sr,Ba)Si₂N₂O₂:Eu²⁺;

(Ca,Sr,Ba)₂SiO₄:Eu²⁺;

(Sr,Ca)AlSiN₃:Eu²⁺;

(Sr,Ca)S:Eu²⁺;

(Sr,Ba,Ca)₂(Si,Al)₅(N,O)₈:Eu²⁺;

(Sr,Ba,Ca)₃SiO₅:Eu²⁺;

α-SiAlON:Eu²⁺;

β-SiAlON:Eu²⁺;

Ca(5-δ)Al(4-2δ)Si(8+2δ)N₁₈O:Eu²⁺; and

other phosphors, luminescent materials such as quantum dots, organicdyes or luminescent glass.

According to at least one embodiment, the conversion material and/ormatrix material is produced on the substrate by doctor blading, screenprinting, stencil printing, dispensing, spray coating, spin coating,electrophoretic deposition or by a combination of these differentmethods.

According to at least one embodiment, the conversion element comprises asubstrate. The substrate can be formed transmissive or transparent. Hereand in the following, a substrate is referred to as transparent if ithas an internal transmission of >90%, preferably >95%, particularlypreferably >99%, in particular in the range of the wavelength of theprimary radiation (laser). Here, internal transmission meanstransmission without reflection at the surfaces (Fresnel reflection).

Alternatively, the substrate can also be formed reflectively, preferablywith a reflectance between 0.95 and 1, in particular in the range of thewavelengths of the primary radiation and/or the secondary radiation.

Materials selected from the following group can be used as substrates:sapphire, ceramics, glass, glass-like materials, glass ceramics, andother transparent or translucent materials. Alternatively, the substratemay comprise a material or a combination of the following materials:aluminum oxide, polycrystalline aluminum oxide, ceramics, aluminum,copper, metals, highly reflective aluminum with or through an appliedcoating system, e.g., of silver or a dichroic coating. The reflectiveformed substrates are suitable for the so-called reflective LARP and thetransparent substrates for the transmissive LARP.

According to at least one embodiment, the substrate comprises a highthermal conductivity of >0.2 W/(m*K), preferably ≥0.5 W/(m*K),particularly preferably ≥0.7 W/(m*K) or to ≥1.0 W/(m*K). In addition,the substrate can comprise good resistance towards moisture, radiationand/or temperatures, which is in particular advantageous for automotiveapplications. For example, the substrate shows no noticeable change intransmissive and reflective properties after, for example, a humiditytest at 85° C. and 85% rel. humidity for >=1000 h. In particular, nonoticeable change means no measurable change or a maximum of 5%deterioration in the primary and/or secondary wavelength range. The sameapplies to the long-term temperature resistance at >=180° C.,better >=200° C. for >=1 h, better >=5 h, ideally >=10 h as well as tothe radiation resistance. Diamond has a thermal conductivity ofapproximately 2300 W/m*K. Sapphire of approximately 40 W/m*K. Both arevery suitable for transparent materials. Glass has a thermalconductivity of about 0.75 W/m*K depending on the material.

The substrate can be structured. For example, the substrate may be astructured sapphire substrate or may be formed as one or moremicrolenses structured on the surface. The substrate may comprise aphotonic crystal lattice on the surface. This is advantageous, inparticular to increase light incoupling and/or decoupling and thusincrease efficiency. On the other hand, an improved angle emissioncharacteristic or beam shaping in one or several directions can beachieved. The surface of the substrate can be modified by roughening,sandblasting, grinding, polishing or etching.

The substrate may comprise a coating. The coating can, for example,comprise a scattering layer to increase light decoupling.

According to at least one embodiment, the conversion element comprisescoatings. The coatings can be subordinate to the matrix material. Thecoatings can also be referred to as encapsulation. The encapsulation isintended to protect against environmental influences such as moisture.

The substrate may comprise functional coatings such as dichroic orinterference coatings. These coatings may have antireflective propertiesor filter properties, such as transmission or reflection of certainwavelength ranges. For the so-called transmissive LARP applications,dichroic coatings are preferably used, which transmit most of the lightemitted by the laser source and reflect most of the light emitted by theconversion material. It is advantageous if the dichroic coating or thelayer stack is arranged between the substrate and the matrix materialand the excitation takes place from the substrate side by a laser beam.Thus, a higher efficiency can be achieved because the transmission ofthe excitation laser beam can be increased and a large part of theemitted or scattered converted light in the direction of the substrateis reflected again in the forward direction.

The dichroic coating can be applied to the sapphire side facing thematrix material containing layer. In general, a dichroic coatingconsists of several thin layers with refractive index differences inorder to use interferences for the wavelength- and direction-dependentchange of radiation in the system. Here, the dichroic coating can havetwo main functions: On the one hand, it ensures a high transmission ofthe incoming laser radiation and, on the other hand, a high reflectivityof the converted light coming from the conversion element. Both effectsincrease the efficiency or effectiveness of the inverter system becausemore light could be used in the interesting top hemisphere. Thisfunctionality is known to a person skilled in the art and is thereforenot explained in detail at this point.

The dichroic coating described above can alternatively or additionallybe arranged on an arbitrary further outer side of the substrate and/oron its edge sides and/or on the side of the conversion element facingaway from the substrate.

The substrate may comprise other configurations. For example, thesubstrate can be structured.

According to at least one embodiment, the conversion material is capableof absorbing the radiation of the laser source and converting it intoradiation with a different longer wavelength and emitting it.

The conversion material may be capable of fully absorbing the radiationof the laser source, in particular of one or more laser beams, andemitting it with a different longer wavelength. In other words, aso-called full conversion takes place, so that the radiation of thelaser source contributes not at all or to less than 5% of the resultingtotal radiation.

Alternatively, the conversion material is capable of partially absorbingthe radiation of the laser source so that the total radiation exitingthe conversion element is composed of the laser radiation and theconverted radiation. This can also be referred to as partial conversion.The total radiation can be white mixed light.

According to at least one embodiment, the conversion material in thematrix material comprises a fraction of more than 50 wt %, better morethan 60 wt %, preferably more than 65 wt % or more than 70 wt % or morethan 75 wt % or more than 80 wt % or more than 85 wt % or more than 90wt % or more than 95 wt %. The conversion material may comprises avolume fraction, for example, of more than 10 or 20 vol %, better morethan 30 vol %, preferably more than 35 vol % or more than 40 vol % ormore than 45 vol % or more than 50 vol % or more than 55 vol % or morethan 60 vol % or more than 65 vol % or more than 70 vol % or more than75 vol % in the matrix material. For example, the volume fraction isbetween 40 vol % and 85 vol % and the mass fraction is between 60 wt %and 90 wt %. This can provide a conversion element that is formed verythinly and comprises a high concentration of conversion material. Theproportion of matrix material in the conversion element, for example, ismax. 70 Vol %, better max. 65 Vol %, preferably max. 60 Vol % or max. 55Vol % or max. 50 Vol % or max. 45 Vol % or max. 40 Vol % or max. 35 Vol% or max. 30 Vol % or max. 25 Vol % or max. 20 Vol % or max. 15 Vol % ormax. 10 Vol % or max. 5 Vol %. This corresponds, for example, to aweight fraction of max. 60 wt %, better max. 55 wt %, preferably max. 50wt % or max. 45 wt % or max. 40 wt % or max. 35 wt % or max. 30 wt % ormax. 25 wt % or max. 20 wt % or max. 15 wt % or max. 10 wt % or max. 5wt % of matrix material in the conversion element. For example, thevolume fraction of the matrix is between 10 vol % and 65 vol % and themass fraction between 5 wt % and 40 wt %.

According to at least one embodiment, the conversion element comprises aporosity of more than 0.1 vol % or more than 1 vol % or more than 2 vol% or more than 5 vol % or more than 10 vol %, better more than 15 vol %,preferably more than 20 vol % or more than 25 vol % or more than 30 vol% or more than 35 vol % or more than 40 vol % or more than 45 vol % ormore than 50 vol % in the matrix material.

According to at least one embodiment, the matrix material of condensedsol-gel has a fraction between 10 and 65 vol % or between 5 and 40 wt %.Alternatively or additionally, the refraction difference to theconversion material is >0.2.

According to at least one embodiment, the conversion element can alsocontain organic conversion materials, such as organic dyes, or quantumdots.

According to at least one embodiment, the conversion element comprisesscattering particles or fillers. The scattering particles or fillers canbe, for example, aluminum oxide, aluminum nitride, titanium dioxide,silicon dioxide, zirconium dioxide, zinc oxide, other ceramic as well asvitreous particles, metal oxides or other inorganic particles. Thescattering particles or the fillers can comprise different shapes, forexample, spherical, rod-shaped or disc-shaped, wherein the particle sizecan be between a few nanometers and a few tens of micrometers. Smallerparticles can be used to adjust the viscosity of the suspension duringcoating. Larger particles can contribute to the production of a compactconversion element and/or to the improvement of heat dissipation,humidity resistance, or thickness homogeneity. The scattering can bedifferent and/or the mechanical stability can be improved.

According to at least one embodiment, the conversion element comprisesscattering particles or fillers. The scattered particles or fillers canbe, for example, aluminum oxide, aluminum nitride, barium sulphate,boron nitride, magnesium oxide, titanium dioxide, silicon dioxide,silicon nitride, YAG, orthosilicate, zinc oxide or zirconium dioxide aswell as AlON, SiAlON or combinations or derivatives thereof or otherceramic or vitreous particles, metal oxides or other inorganicparticles. The scattering particles or the fillers can comprisedifferent shapes, for example, spherical, rod-shaped or disc-shaped,wherein the particle size can be between a few nanometers and a few tensof micrometers.

According to at least one embodiment, the conversion element comprisesadditives. An additive can be aerosil or silica, such as sipernate, forexample. Thus, the viscosity of the suspension can be modified and theproportion between the liquid and solid components can be adjusted.

According to at least one embodiment, the conversion element is producedfrom several layers, which can vary in layer thickness, compactness,matrix material, conversion material, scatterers and/or fillers.

According to at least one embodiment, the conversion element comprises amatrix material. The conversion material is incorporated in the matrixmaterial, preferably dispersed. The conversion material can behomogeneously distributed in the matrix material. Alternatively, theconversion material may comprise a concentration gradient in the matrixmaterial, for example, an increase in the concentration of theconversion material in the matrix material in the direction away fromthe laser source. For example, larger particles can be arranged closerto the substrate and smaller particles can be arranged on the surface ofthe conversion element, i.e., on the side facing away from thesubstrate. This reduces backscattering. In particular, thebackscattering of the blue light, i.e., the light emitted by the laserbeam, can be reduced.

According to at least one embodiment, the conversion material and/ormatrix material is each inorganic. The conversion material preferablycomprises no organic dyes as converter material. The matrix materialpreferably comprises no organic materials.

According to at least one embodiment, the matrix material comprises atleast one sol-gel material or consists thereof. Sol-gel materials arereferred to here and in the following as those materials which areproduced by a sol-gel process. The sol-gel process is a method ofproducing inorganic or hybrid polymer materials from colloidaldispersions, the so-called sols. The starting materials are alsoreferred to as precursor materials. In a first basic reaction, finestparticles are formed from them in solution. Powders, fibers, layers oraerogels can be produced by the special further processing of the sols.The essential basic process of the sol-gel process is the hydrolysis ofthe precursor materials and the condensation between the reactivespecies produced thereby. The sol-gel process is sufficiently well knownto a person skilled in the art and will not be explained in detail hereat this point.

The sol-gel material can be condensed. This means that the sol-gelmaterial is produced by condensation.

According to at least one embodiment, the sol-gel material is selectedfrom the following group: water glass, monoaluminum phosphate, modifiedaluminum phosphate, metal phosphate, aluminum phosphate,alkoxytetramethoxysilane, tetraethylorthosilicate,methyltrimethoxysilane, methyltriethoxysilane, titanium alkoxide, silicasol, metal alkoxide, metal oxane, metal alkoxane.

According to at least one embodiment, the matrix material consists ofaluminum phosphate, monoaluminum phosphate or a modified monoaluminumphosphate. Alternatively, the matrix material consists of water glass orwater glass and a chemical hardener. Water glass is defined as vitreous,i.e., amorphous, water-soluble sodium, potassium and/or lithiumsilicates solidified from a melt or their aqueous solutions. Water glassthus differs from conventional glass particularly in its properties suchas porosity.

The matrix material can at least consist of lithium water glass, sodiumwater glass, potassium water glass or a mixture thereof, or comprisethese alkali water glasses. The inventors have recognized that acombination of lithium water glass and potassium water glass inparticular has excellent properties for the matrix material. The ratiobetween lithium water glass and potassium water glass is preferablybetween 1:3 and 3:1. In particular, the ratio between lithium waterglass and potassium water glass is 1:3, 1:1 or 3:1, preferably 1:1.

For example, alkali water glasses may have a module from 1.5 to 5,preferably a module from 2.5 to 4.5.

According to at least one embodiment, the matrix material consists ofwater glass and a chemical hardener, which results in a furtherby-product in addition to any alkali carbonate produced. In the case ofa phosphate hardener, this would be an alkali phosphate.

According to at least one embodiment, the matrix material is free oforganic materials. Preferably, the matrix material is free of siliconeand/or epoxy. This is an advantage because silicones and epoxides candegenerate under the influence of blue light. They do this particularlyunder the influence of high temperatures and high radiation density ofblue or short-wave light, as commonly found in LARP applications.Therefore, if the matrix material contains silicone and/or epoxy, it canirreversibly degenerate. With scanning LARP, this is in particularcritical for a failure of the light-deflecting element, which increasesthe average blue power density in the part of the converter where thespot is located several times over.

According to at least one embodiment, the matrix material comprisesaluminum phosphate, monoaluminum phosphate or a modified monoaluminumphosphate or water glass, wherein the conversion material is capable ofabsorbing the radiation of the laser source and converting it at leastpartially into radiation of a different wavelength, wherein theconversion element is deposited on a substrate of sapphire, wherein thesubstrate is arranged in the beam path of the radiation emitted orabsorbed by the conversion material or in the beam path of the laserradiation.

According to at least one embodiment, the matrix material additionallycomprises a chemical hardener. By adding a chemical hardener, preferablya phosphate, and curing the matrix material, for example, between 150°C. and 350° C. for water glass, it is possible to produce a conversionelement that is very stable towards humidity. In particular, thisconversion element has a high stability at 85° C., 85% relative humidityand woo hours for the test duration, which was determined by means of ahumidity test. Preferably, no chemical hardener is added to aluminumphosphate, monoaluminum phosphate or modified monoaluminum phosphate.The aluminum phosphate, monoaluminum phosphate or modified monoaluminumphosphate described here preferably has a molar ratio of Al to P of 1:3to 1:1.5 and cures in particular at temperatures between 300° C. and400° C. The solutions may contain further elements or compounds, butpreferably a maximum of 1 mol % of alkali and halogen compounds.

The inventors have recognized that when using water glass or aluminumphosphate or monoaluminum phosphate or modified monoaluminum phosphate,a conversion element can be produced with an inorganic matrix materialthat can be cured at low temperatures with long-term stability comparedto organic matrix materials or organic sol-gel materials such asalkoxisilanes (TEOS), alkoxides, and alkoxanes. Low curing temperaturesare advantageous to avoid damages to the substrate, for example, or toan encapsulation or another coating, such as a dichroic coating. Apermanent or lasting damage of the phosphor during the embedding processis also avoided or minimized. The use of organic or partially organicsol-gel materials is possible, but not preferred, because the chemicalreaction is not complete at such low temperatures. This can lead toinstability of the conversion element and thus to a reduction inlifetime.

According to at least one embodiment, the laser source comprises atleast one laser beam with a dominant wavelength of 410-490 nm,preferably 430-470 nm, particularly preferably 440-460 nm.Alternatively, more than one laser beam, for example, six laser beams,can form the laser source, which is guided together as a stack inparallel over the converter. One or more lasers with the same ordifferent wavelengths can be used as the laser source.

According to at least one embodiment, the laser beam comprises awavelength from the blue spectral range. Alternatively, otherwavelengths such as those selected from the UV, green, yellow, orangeand red spectral range can also be used.

According to at least one simple embodiment, the radiation of the lasersource impinges directly on the conversion element during operation. Inother words, no further layers, elements, lenses or optical elements arearranged between the laser source and the conversion element. Usually,however, especially when using several laser diodes, a primary opticalsystem is used to pre-collimate the laser light, possibly combine it ina beam combiner and form the beam path. Depending on the application andinstallation space, this primary optics can contain all common elements,e.g., lenses and lens stacks/arrays, or also reflective opticalelements. The use of refractive optical elements is also possible. Theuse of dichroic mirrors is also possible. This can be formed fromseveral layers and, for example, have an alternating sequence oftitanium dioxide and silicon dioxide layers.

Furthermore, the system can be used as reflective LARP and transmissiveLARP with respect to the converter element. Reflective LARP refers to asystem in which, unlike transmissive LARP, the laser does not exitopposite the entrance side of the laser radiation of the conversionmedium, but is reflected and exits also at the original entrance side ofthe laser radiation.

According to at least one embodiment, the conversion element is formedas a layer with a maximum layer thickness of 70 μm, better maximum 60μm, preferably maximum 50 μm or maximum 45 μm or maximum 40 μm ormaximum 35 μm or maximum 30 μm or maximum 25 μm or maximum 20 μm forpartial conversion. For full conversion, the conversion element isformed with a maximum layer thickness of 150 μm, better 130 μm maximum,preferably maximum 110 μm or maximum 90 μm or maximum 80 μm or maximum70 μm or maximum 60 μm or maximum 50 μm or maximum 40 μm.

For example, the conversion element has a layer thickness between 10 and30 μm after curing. As an advantage, the heat generated in theconversion material can be easily dissipated and spot widening can bekept to a minimum.

Embodiments provide an optoelectronic component. Preferably, theoptoelectronic component comprises a conversion element described here.All definitions and specifications of the conversion element also applyto the optoelectronic component and vice versa.

According to at least one embodiment, the component comprises a lasersource that emits radiation during operation, a conversion element whichat least partially converts the radiation emitted by the laser sourceinto a radiation with a different longer wavelength, and a layer stackwhich is arranged between the laser source and the conversion elementand at least partially reflects the radiation emitted by the conversionelement and is permeable to the radiation emitted by the laser source.The conversion element comprises a substrate which may have a dichroiccoating. The dichroic coating can transmit the light of the laser sourcemainly at perpendicular or nearly perpendicular incidence, while itpartly reflects it at larger angles, for example, when laser light isbackscattered in the conversion element and impinges on the dichroicmirror at different angles.

The layer stack can be formed from titanium dioxide and silicon dioxidelayers, which are preferably arranged alternately. The layer stack islocated between the laser source and the conversion element. Theradiation emitted by the conversion element can thus be reflected by thelayer stack and the radiation emitted by the laser source can passthrough the layer stack. Alternatively, the layer stack can be composedof tantalum (V) oxide and silicon dioxide layers.

According to at least one embodiment, the radiation of the laser sourceis arranged dynamically or statically to the conversion element.

According to at least one embodiment, the radiation of the laser sourceimpinges on the conversion element via a transmissive substrate duringoperation.

Embodiments also provide an optoelectronic component. All specificationsmade about the conversion element and its production also apply to theoptoelectronic component and vice versa.

According to at least one embodiment, the optoelectronic componentcomprises: a laser source that emits radiation during operation, aconversion element described herein comprising a dichroic layer stackarranged between substrate (2) and matrix material (3), wherein at leasta part of the radiation of the laser source (1) transmits the substrateand the dichroic layer stack, and the conversion material (4) convertsthe transmitted radiation into radiation of different longer wavelength,wherein the converted radiation is reflected by the dichroic layerstack.

Further embodiments provide a method for producing a conversion element.The method described here is preferably used to produce the conversionelement described here. All definitions and specifications of theconversion element also apply to the method for producing a conversionelement and vice versa.

In at least one embodiment, the method of producing a conversion elementcomprises the steps: A) providing a matrix material, B) introducing aninorganic wavelength converting conversion material into the matrixmaterial, wherein the matrix material is condensed and is produced orcross-linked by a sol-gel process at a temperature between 150° C. and400° C., wherein the matrix material is selected from the followinggroup: water glass, metal phosphate, aluminum phosphate, monoaluminumphosphate, alkoxytetramethoxysilane, tetraethylorthosilicate,methyltrimethoxysilane, methyltriethoxysilane, titanium alkoxide, silicasol, metal alkoxide, metalloxane, metalalkoxane, and C) applying thematrix material and conversion material directly on a substrate. Thesubstrate may have a dichroic coating arranged directly on the matrixmaterial or conversion material.

With the conversion element described here, a smaller emitting lightspot can be produced. This results in a better contrast between thesurfaces which are to be illuminated and those which are not to beilluminated. This can be observed, for example, by reduced scatteredradiation or a reduced halo or corona environment around the illuminatedsurface in comparison to ceramic converters, for example.

These advantages can be applied in particular in so-called scanning LARPsystems for the automotive field. In addition, the conversion elementsdescribed here may have a higher luminance compared to ceramicconverters. With other conversion elements, the spot widening is oftenso bad that the light area on the conversion element has to be definedby an additional aperture in order to avoid an unintended halo or coronaeffect. With embodiments of the present invention, it may be possible toomit such an aperture due to the small spot widening, thus reducingcosts.

In addition, the efficiency can be increased, in particular forcomponents with a high energy density and/or temperatures due to betterheat dissipation. This reduces the temperature in the conversionmaterials and thus the thermal quenching of the conversion materialscompared to organic matrix materials, which usually have a significantlypoorer thermal conductivity of <0.5 W/(m*K). The maximum operatingperformance and/or temperature can be increased before the so-called“thermal rollover” of the conversion material is generated orirreversible damage to the conversion element is caused.

The thermal rollover can occur as follows:

1. Heat is generated in the conversion element during operation (due toStokes heat when converting from, for example, blue to yellow; due tolosses due to quantum efficiency <100% or due to absorption).

2. At higher temperatures, most conversion materials possess thermalquenching, i.e., the quantum efficiency decreases as the temperaturerises.

3. By thermal quenching, more heat is produced, which can lead to evenmore thermal quenching.

4. Thermal rollover occurs when, despite an increase in laser power(excitation), the total radiation or the converted radiation does notcontinue to rise but possibly even falls.

According to at least one embodiment, no adhesive layer is arrangedbetween the substrate and the matrix material and/or conversionmaterial. In other words, the matrix material with conversion materialcan be applied or attached directly to or on the substrate, for example,directly on the coating of the substrate. In comparison, ceramicconverters have to be adhered, wherein the adhesive usually has a lowthermal conductivity and maximum thermal resilience.

The production of the conversion material described here is cheapercompared to ceramic converters which have to be adhered to a substrate,in particular if different inorganic conversion materials are to beproduced in one process step, for example, by spray coating or doctorblading. This means that several elements are processed at once, i.e.,it is more practical and cheaper to adhere than individual ceramicconverters. In addition, different conversion materials (e.g., garnetswith different doping or different Al/Ga or Lu/Y content) or a mixtureof conversion materials can be used for the conversion element describedhere. The conversion materials described here therefore have greaterflexibility than ceramic converters with regard to setting the colorlocation or the color rendering index (CRI) of the total radiation.

According to at least one embodiment, the conversion element is used inthe automotive field, for example, in headlights. Alternatively, theconversion element can be used, for example, in projection applications,endoscopy or stage lighting.

The conversion element can be produced as a composite on a sapphirewafer. After the sapphire wafer has been coated, it can be separated,for example, by sawing. Such a process can improve homogeneity and yieldand reduce process costs.

According to at least one embodiment, more than one conversion materialis embedded in the matrix material. This allows the color location orcolor rendering index (CRI) to be adjusted. For example, a combinationof green and red conversion materials can produce warm white mixedlight. The change of the color location can change the visibility of aheadlight or in a vehicle, for example, in rain, snow or fog.

According to at least one embodiment, the conversion material has anaverage particle diameter between 1 and 25 μm, in particular between 2and 15 μm, preferably between 3 and 9 μm.

According to at least one embodiment, the conversion element isactivated with an activator or dopant. The concentration of the dopantcan be between 0.1% and 10%, for example, 3%, as with(Y_(0.97)Ce_(0.03))₃Al₅O₁₂. As dopant, for example, lanthanides or rareearths can be used, for garnet phosphors in particular Ce.

According to at least one embodiment, the conversion element has noholes. This means inhomogeneities in the conversion element, such aspores or other holes which are configured to transmit blue light withoutconversion or scattering. This can be influenced, for example, by theparticle size of the conversion materials or by the dopant concentrationor by the addition of fillers or scattering particles or by filling thepores or holes with additional (preferably inorganic) material. This isparticularly important if a collimated laser light is to be scattered orconverted by the conversion element.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, advantageous embodiments and further developmentsresult from the following embodiments described in connection with thefigures.

FIGS. 1A to 2F show conversion elements according to embodiments;

FIGS. 3A to 3I show electron microscopic images of conversion elementsaccording to embodiments; and

FIGS. 4A to 5B show the luminance according to an embodiment andcomparison examples.

In the exemplary embodiments and figures, identical, similar orsimilarly acting constituent parts are provided with the same referencesymbols. The depicted elements and their size relationships among oneanother should not be regarded as true to scale. Rather, individualelements such as layers, components, devices or areas may beexaggeratedly displayed too large for better representability and/orbetter understanding.

For example, FIGS. 1A and 1B show substrate 2, which is thinner than thelayer thickness of the layer with matrix material 3, although thepreferred layer thickness of substrate 2 (approx. 500 μm) is greaterthan the layer thickness of the layer with matrix material 3 (approx. 25μm).

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1 shows a schematic cross-sectional illustration of a conversionelement 100 according to an embodiment. The conversion element 100comprises a substrate 2 on which a matrix material 3 is arranged. In thematrix material 3, the conversion material 4 is introduced, which isconfigured for wavelength conversion. In this example, the conversionmaterial 4 is homogeneously distributed in the matrix material 3. FIG.1B shows the distribution of conversion material 4 in matrix material 3using a concentration gradient or grain size gradient. Larger particlesof the conversion material 4 are arranged towards substrate 2, smallerparticles are arranged towards the opposite side of substrate 1. Matrixmaterial 3 can be, for example, water glass or monoaluminum phosphate ormodified monoaluminum phosphate. A garnet such as YAG:Ce can be used asconversion material 4.

FIGS. 2A to 2D each show a side view of a conversion element 100according to an embodiment that is arranged in a LARP arrangement. Thedistance laser-conversion element can comprise several cm.

FIG. 2A shows a laser source 1 that is configured to emit a primaryradiation or first radiation 5. The first radiation 5 impinges directlyon substrate 2, which is, for example, sapphire and is transmissivelyformed. The matrix material 3 and the conversion material 4 aresubordinate to the substrate 2. The conversion material 4 absorbs theprimary radiation 5 and emits a secondary radiation 6. The conversionelement 100 can be designed for full conversion or partial conversion.Preferably, the conversion element 100 is adhesive-free here or in theother exemplary embodiments.

The conversion element according to FIG. 2B shows a substrate 2 that isformed reflectively. The substrate 2 extends over the base side of thematrix material 3, in which the conversion material 4 is embedded, andto a side surface of the matrix material 3. The primary radiation 5emitted by the laser source 1 thus impinges directly on the matrixmaterial 3, is converted by the conversion material 4 into radiation ofdifferent wavelength, and is reflected on the substrate 2. The lasersource 1 can be arranged on a heat sink 8. Both the laser source 1 andthe matrix material 3 and substrate 2 can also be arranged on a carrier7. The carrier 7 can be, for example, a printed circuit board. Here, thelaser beam 5 can irradiate vertically and/or at a certain angle to theconversion element 100.

In the embodiments of FIGS. 2A and 2B, the conversion element is mountedmechanically immovable with respect to the laser source. The laser beamof the laser source 1 may be capable of scanning or moving on thesurface of the conversion element 100. This does not preclude that whenthe laser beam moves, the laser source 1 is mechanically immovable withrespect to the conversion element 100.

FIG. 2C shows the arrangement of laser source 1 at an angle to substrate2 and matrix material 3. The same applies to the conversion elementaccording to FIG. 2D. In the conversion element of FIG. 2D, the lasersource 1 is integrated into a light guide. Matrix material 3 andsubstrate 2 can be designed analogously to the previous embodiments. InFIG. 2C, laser source 1 and substrate 2 with matrix material 3 are notarranged on a common carrier. The primary radiation 5 can impinge on thesubstrate 2 or matrix material 3 in a free-running manner, as shown inFIG. 2C, or via a light guide, as shown in FIG. 2D. The substrate 2 isformed transmissively. In the case of a reflective substrate 2, it isfacing away from the laser beam 5 and impinges first on the matrixmaterial 3.

Between laser source 1 and the conversion element 100, optical elementssuch as lenses or collimators can be arranged (see FIG. 2F).

FIG. 2E essentially corresponds to the embodiment of FIG. 2A. UnlikeFIG. 2A, FIG. 2E comprises a dichroic coating 21 and/or ananti-reflection coating 22 as part of substrate 2. The dichroic coating21 is arranged directly on the matrix material 3. The anti-reflectioncoating 22 is arranged on the side of substrate 2 facing away frommatrix material 3.

FIGS. 3A to 3I each show scanning electron microscopic images of aconversion element 100.

FIG. 3A shows a side view of an electron microscopic image of theconversion element 100 with water glass as matrix material 3, markedhere with area 1. The conversion element 100 can be used for aheadlight. Potassium water glass with a chemical hardener, for example,aluminum phosphate, is used as matrix material 3. The chemical curing iscarried out by ion exchange, in this case potassium ions by aluminumions. This means that aluminum ions are incorporated into the silicatenetwork, which increases humidity resistance. Potassium phosphate isproduced as a by-product.

The conversion material 4 is in particular a garnet, such as YAGaG:Ce,which emits radiation from the yellow spectral range and is formedfine-grained. The substrate 2, here marked with area II in the image, issapphire and has a dichroic/interference layer stack, in particular ofsilicon dioxide and titanium dioxide, which is here not visible in theelectron microscopic image. In particular, the layer stack has athickness of approx. 3 μm. In particular, substrate 2 has a layerthickness of approx. 500 μm. The layer of water glass and conversionmaterial has a thickness of approximately 25 μm. To the right of thislayer of water glass and conversion material, an air layer is arranged,here marked area III. D indicates the working distance, U indicates thehigh voltage and V the magnification.

The proportion in weight percent of the conversion material 4 andchemical hardener to potassium water glass and water is 1:0.9 wt %,i.e., 52.5 wt % solid particles in a suspension. Without considering thecuring agent, the conversion material to potassium water glass and wateris 1:1.03 wt %, i.e., 49.2 wt % or 15.3 vol % conversion material in thesuspension. After curing without considering the hardener and water, theproportion of conversion material to potassium water glass is 1:0.25 wt%, i.e., 80 wt % conversion material 4 in the conversion element 100.This corresponds to a volume proportion of approx. 55% of the conversionmaterial 4 or approx. 45 vol % or 20 wt % of the matrix material 3 inthe conversion element 100.

FIG. 3B shows a corresponding top view of the electron microscopic imageshown in FIG. 3A.

For the image of FIG. 3C, water glass was also used as matrix material 3for the conversion element 100.

A suspension of potassium water glass was used as solution, aluminumphosphate as chemical hardener and a garnet phosphor YAGaG:Ce asconversion material 4. Optionally, the suspension was diluted withwater. The mass ratio of solid components to liquid components in thesuspension varied between 1:2 and 1:0.5, in particular between 1:1 and1:0.8, preferably 1:0.5. The suspension was applied to a substrate 2,for example, by doctor blading, so that the wet coating has a layerthickness between 10 μm and 150 μm, in particular between 20 μm and 100μm, particularly preferably between 30 μm and 80 μm. Subsequently, thecoated substrate 2 was dried and cured at a temperature of between 150°C. and 350° C. The electron microscopic images (SEM) as shown in FIG. 3Awere then taken. After drying and curing at 350° C., the coatingthickness is approx. 30 μm. This conversion element 100 already shows adegree of conversion too high for typical cold white applications, suchas headlight applications. For car headlight applications, the coatingcould be even thinner to achieve the appropriate color location.

By using the conversion material with a small particle size and a highactivator concentration, layers with a layer thickness of only 10 μm to20 μm can be produced after drying and curing. Such conversion elements100 are advantageous in terms of heat dissipation and spot widening. Theelectron microscopic image of FIG. 3C shows from left to right an airlayer (area I), the substrate 2 (area II), the matrix material 3 and theconversion material 4 (area III) and an air layer (area IV).

The FIG. 3D shows an example of an electron microscopic image, wherein amixture of different water glasses is used as matrix material 3. Here, asuspension of a mixture of potassium water glass and lithium water glassas solution and a garnet (YAG:Ce) was used. Optionally, the solution canalso be diluted with water. The mass ratio of the water glass is between1 to 99 wt % lithium water glass and 99 to 1 wt % potassium water glass,in particular between 10 and 90 wt % lithium water glass and 90 and 10wt % potassium water glass, particularly preferred between 25 and 75 wt% lithium water glass and 75 to 25 wt % potassium water glass,particularly preferred between 40 to 60 wt % lithium water glass and 60to 40 wt % potassium water glass. In this sample, the mass ratio was 50wt % lithium water glass to 50 wt % potassium water glass. The massratio between the solid and liquid components in the suspension variedbetween 1:1 and 1:0.1, preferably between 1:0.6 and 1:0.2, in particularbetween 1:0.4 and 1:0.3. In this sample the ratio was 1:0.36. Thecoating and the temperature treatment are carried out analogously to theexample in FIG. 3C. FIG. 3D shows the electron microscopic image of asample which was cured at 150° C. This sample is stable in the 1000 hourtest at 85° C. and 85% relative humidity. After curing, the proportionof the matrix material (3) is only approx. 10 wt % or approx. 15 vol %,resulting in a conversion element 100 with a high degree of conversionmaterial (4) filling.

FIGS. 3E and 3F show top and side views of electron microscopic images,wherein potassium water glass with a hardener is used as matrix material3. Matrix material 3 is excellently suited to provide a high efficiencyconversion element 100. The structures are very porous compared tonormal phosphor in glass (phosphor in glass, PiG).

FIG. 3G shows an electron microscopic image, wherein aluminum phosphateis used as matrix material 3. Here, a suspension of modifiedmonoaluminum phosphate as solution and a garnet (YAGaG:Ce) was used. Themass ratio of the solid components to the liquid components in thesuspension is between 1:2 and 1:0.5, particularly preferred between1:1.5 and 1:0.9, particularly preferred between 1:1.3 and 1:1. Thesuspension is applied to a substrate, for example, by doctor blading,wherein the wet coating has a layer thickness between 10 and 150 μm,preferably between 20 and 100 μm, particularly preferably between 30 and80 μm. Subsequently, the substrate is dried and cured at a temperaturebetween 300° C. and 400° C. After drying and curing at 350° C., thelayer thickness is approx. 35 μm and the matrix content is approx. 60vol % or approx. 30 wt %. Due to the higher matrix content, the gapsbetween the fluorescent grains are filled up more, resulting in lowerporosity and a more closed surface than in the examples with water glassas matrix. The refractive index of the matrix is approx. 1.5 and that ofthe embedded conversion material is approx. 1.8, resulting in a highrefraction difference, which is further intensified by the porespresent. This results in a high scattering, which positively affects thelight-dark contrast of the illuminated surface. With water glass, therefraction difference between the materials is similar, but due to thehigher porosity, these layers scatter even more strongly and thereforeshow an even smaller beam width and an even better light-dark contrastthan the layers with aluminum phosphate matrices in conjunction with ahigh luminance.

The electron microscopic SEM images of the FIGS. 3A, 3C, 3D, 3F, 3G and3I show a side view of a broken conversion element 100.

FIGS. 3H and 3I show the top view and side view of electron microscopicimages of the exemplary embodiments for aluminum phosphate matrix. Withthis matrix material a highly efficient conversion element 100 can beprovided. Excellent adhesion and separation results can be achieved. Inaddition, the matrix material has a porous structure, which can also beproduced more densely. The conversion elements can therefore be producedcost-effectively in wafer size. These are then cut into smallerconversion elements, for example, using a diamond saw. Good adhesion ofthe layer and good layer stability are required to prevent chipping orbreaking at the edges during sawing.

FIG. 4A shows the spatially resolved luminance of a so-called staticLARP component according to an embodiment with water glass as matrixmaterial 3. Static measurement here means that the laser source 1 isdirected at the conversion element 100 without the beam of the lasersource 1 moving on the conversion element 100. The blue excitation ofthe laser beam is approximately 50 μm×250 μm (1/e².). The area comprisesthe intensity range which is within the 1/e² value of the maximum. Ablue input power of approximately 0.66 W is set. The convertertemperature is 80° C. Substrate 2 is a sapphire substrate with adichroic coating or a dichroic layer stack and may have ananti-reflection coating on the opposite side. The width of the image isapproximately 1 mm. The measurements show that the emission spot for theconversion material 4 in the matrix material 3 water glass is smallerthan for a ceramic converter (FIG. 4B).

FIG. 4C shows each the luminance of a dynamic LARP component accordingto an embodiment with water glass as matrix material 3 with L_(max)approx. 110 Mcd/m². Dynamic means that the laser beam scans theconversion element 100, i.e., moves on the conversion element 100. Thescanning frequency is 133 Hz. A blue excitation with approximately 50μm×250 μm (1/e²) takes place. The blue input power is approximately 1.6W and the converter temperature is 80° C. Substrate 2 is a sapphiresubstrate with a dichroic layer stack located between the substrate andconversion element. On the opposite side of the substrate (laser-facingside), the substrate has an anti-reflection layer. The width of thescanning image is approximately 9.5 mm.

FIG. 4D shows a comparison example with a ceramic converter which isadhered to the dichroic layers of the substrate with silicone. Acomparison with images 4C and 4D shows that the conversion element 100according to an embodiment has excellent optical properties, as the beamwidth in the conversion element is also significantly smaller here,resulting in a better light-dark contrast. This is particularlyimportant for an automotive application.

FIG. 5A shows the relative luminance in a.U. (arbitrary units) as afunction of the distance d in μm of the laser beam 1-1, a conventionalceramic converter 1-2 and a conversion element 1-3 according to anembodiment formed as a dynamic LARP. The scanning frequency is 133 Hz.The blue excitation spot is approximately 50 μm×250 μm (1/e²). The blueinput power is approximately 1.6 W. The converter temperature is 80° C.The substrate used was a sapphire substrate with a dichroic layer stackand an anti-reflection coating. FIG. 5A shows the advantage of theconversion element 100 with the matrix material water glass compared toconventional ceramic converters in that the emitted light is pronouncedsignificantly smaller at comparable luminance, i.e., has less spotwidening. This means that less halo/corona/scattered light is producedand thus a better light-dark contrast is available. The 1/e² width is250 μm for the conversion element 100 with water glass and 575 μm forthe ceramic converter.

FIG. 5B shows the luminance curve L in cd/m² of a conventional ceramicconverter 1-1 and a conversion element 1-2 according to an embodiment asa dynamic LARP component. For the scanning frequency, the blueexcitation spot, the power, the converter temperature and the substrate,the same specifications apply as for FIG. 5A. Here, too, the conversionelement 100 with the matrix material water glass shows a smallerhalf-width than the conventional ceramic converter. The peak of theconversion element of the embodiment is higher than the peak of theconventional ceramic converter, which means a higher luminance. Inaddition, the spot widening of the conversion element of the embodimentis smaller. The contrast, here indicated as the ratio of the intensityat a distance of 1 mm from the peak to the peak intensity, is approx.1:95 for the water glass and approx. 1:30 for the conventional ceramic.The intensity of the conversion element of the embodiment decreasesfaster with increasing distance from the peak than for the ceramicconverter. This results in less halo/corona/scattered light in theconversion element of the embodiment and thus a better light-darkcontrast.

The exemplary embodiments described in conjunction with the figures andtheir features can also be combined with each other according to furtherexemplary embodiments, even if such combinations are not explicitlyshown in the figures. Furthermore, the exemplary embodiments describedin conjunction with the figures may have additional or alternativefeatures as described in the general part of the description.

The invention is not limited by the description of the exemplaryembodiments to these. Rather, the invention includes each new featureand each combination of features, which in particular includes eachcombination of features in the patent claims, even if that feature orcombination itself is not explicitly stated in the patent claims orexemplary embodiments.

What is claimed is:
 1. An arrangement comprising: a conversion elementcomprising: a wavelength converting conversion material; a matrixmaterial in which the conversion material is embedded; and a substrateon which the matrix material with the embedded conversion material isdirectly arranged, wherein the matrix material comprises at least onecondensed sol-gel material, wherein the matrix material comprises atleast lithium water glass, sodium water glass, potassium water glass ora mixture thereof, wherein the lithium water glass, the sodium waterglass, the potassium water glass or the mixture thereof has a modulefrom 1.5 to 5; and a laser source configured to emit primary radiationduring operation, wherein the conversion element is arranged in a beampath of the laser source, wherein the conversion element is mechanicallyimmovably mounted with respect to the laser source, and wherein theprimary radiation of the laser source is dynamically arranged to theconversion element.
 2. The arrangement according to claim 1, wherein theconversion material is configured to absorb the primary radiation and toconvert the primary radiation at least partially into secondaryradiation of a different wavelength, wherein the substrate is a sapphiresubstrate, and wherein the substrate is arranged in the beam path of theprimary radiation or the secondary radiation.
 3. The arrangementaccording claim 1, wherein the conversion material and the matrixmaterial comprise inorganic materials.
 4. The arrangement according toclaim 1, wherein the matrix material comprises the condensed sol-gelwith a proportion of between 10 and 65 vol %, and wherein a refractiondifference to the conversion material is >0.2.
 5. The arrangementaccording to claim 1, wherein the laser source is configured to emit theprimary radiation with a dominant wavelength between 430 nm and 470 nminclusive.
 6. The arrangement according to claim 1, wherein the matrixmaterial is free of silicone and/or epoxy.
 7. The arrangement accordingto claim 1, wherein the matrix material consists essentially of thelithium water glass, the sodium water glass, the potassium water glassor the mixture thereof, and a chemical hardener.
 8. The arrangementaccording to claim 1, wherein the matrix material consists essentiallyof the lithium water glass, the sodium water glass, the potassium waterglass or the mixture thereof.
 9. The arrangement according to claim 1,wherein the arrangement is a layer with a maximum layer thickness of 40μm.
 10. The arrangement according to claim 1, wherein the conversionelement comprises a porosity of more than 0.1 vol % in the matrixmaterial.
 11. The arrangement according to claim 1, wherein theconversion material is selected from the group consisting of garnet,orthosilicate, and nitridosilicate.
 12. The arrangement according toclaim 1, wherein the matrix material comprises the condensed sol-gelwith a proportion of between 5 and 40 wt %, and wherein a refractiondifference to the conversion material is >0.2.
 13. An arrangementcomprising: a conversion element comprising: a wavelength convertingconversion material; a matrix material in which the conversion materialis embedded; and a substrate on which the matrix material with theembedded conversion material is directly arranged, wherein the matrixmaterial comprises at least one condensed sol-gel material, wherein thematrix material comprises lithium water glass and potassium water glass,wherein a ratio between the lithium water glass and the potassium waterglass is between 1:3 and 3:1; and a laser source configured to emitprimary radiation during operation, wherein the conversion element isarranged in a beam path of the laser source, wherein the conversionelement is mechanically immovably mounted with respect to the lasersource, and wherein the primary radiation of the laser source isdynamically arranged to the conversion element.
 14. The arrangementaccording to claim 13, wherein the conversion material is configured toabsorb the primary radiation and to convert the primary radiation atleast partially into secondary radiation of a different wavelength,wherein the substrate is a sapphire substrate, and wherein the substrateis arranged in the beam path of the primary radiation or the secondaryradiation.
 15. The arrangement according claim 13, wherein theconversion material and the matrix material comprise inorganicmaterials.
 16. The arrangement according to claim 13, wherein the matrixmaterial comprises the condensed sol-gel with a proportion between 5 and40 wt %, and wherein a refraction difference to the conversion materialis >0.2.
 17. The arrangement according to claim 13, wherein the matrixmaterial is free of silicone and/or epoxy.
 18. The arrangement accordingto claim 13, wherein the conversion element comprises a porosity of morethan 0.1 vol % in the matrix material.
 19. The arrangement according toclaim 13, wherein the conversion material is selected from the groupconsisting of garnet, orthosilicate, and nitridosilicate.